Boysenberry blooms, no fruit

For the third year in a row our boysenberry plant has bloomed prolifically, and gotten lots of bee visits, but never set any fruit. Last year I tried pollinating it with a brush. I’m no expert, but the plant looks healthy. Do I need two for pollination? There are two varieties of upright blackberries right next to it (Kiowa and Arapaho). Their bloom times overlap with the boysenberry, and both of them have set fruit each year. Think it’s time to give up and put something productive in the space, or am I overlooking something?

Odd… supposed to be self pollinating.

Not sure what would cause that.

I have a few plants. One for the first three year bloomed but had no fruit even though the one before and after it had fruit. I wondered if it might be frost damage as it was behind a building. Last year I had fruit will see if this year what’s going on. Hopefully yours will work itself out